After admitting to goosing mpg numbers, investigators looked for what went wrong.

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On Tuesday, investigators in Japan released a report attempting to explain how Japanese automaker Mitsubishi was able to falsify its fuel economy numbers on certain cars sold in Japan. The three-month-long investigation pointed to a “collective failure,” at an executive level, to deal with concerns that employees brought up.

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The automaker’s cheating was discovered earlier this year when Nissan, which rebrands some of Mitsubishi’s cars and sells them in Japan, found discrepancies in emissions rates between reported and real-world mileage. Mitsubishi later admitted to having falsified data for more than 25 years, in some cases overstating fuel economy by 16 percent, according to CBS News. Nissan’s discovery crushed Mitsubishi’s share price. Since then, Nissan scooped up 34 percent of Mitsubishi for a bargain $2.2 billion (¥237 billion).

In an unrelated discovery in March, Japan’s Department of Transportation publicly called out Mitsubishi, as well as Toyota and Nissan, for selling diesel cars with higher-than-allowed nitrogen oxide (NOx) emissions in Japan, echoing the scandal that has embroiled Volkswagen since last September in the US.

The investigation into Mitsubishi’s practices echoes what little we know about Volkswagen’s corporate culture. Mitsubishi executives apparently were not directly involved in cheating, but they dismissed concerns from employees about falsified numbers, set unreasonable goals, and never checked to see how well those goals were being met.

“Questions over measurement methods for calculating driving resistance were also raised during a company event in 2005 but went unheeded,” The Wall Street Journal reports.

The Mitsubishi investigation was conducted by three lawyers and a former Toyota director, and it included interviews with more than 150 Mitsubishi employees. The company maintains that it never falsified data on cars sold outside of Japan. Mitsubishi has apparently committed to paying back its Japanese customers for the extra gas they bought for cars with worse fuel economy than they thought they were getting.